1. Field of the Invention
The present invention relates to an inkjet recording head cartridge provided integrally with an inkjet recording head unit configured to perform recording by discharging liquid, such as ink, and with an ink accommodating unit configured to supply ink to the recording head unit. More particularly, the present invention relates to an inkjet recording head cartridge configured to discharge plural kinds of micro ink droplets.
2. Description of the Related Art
One of the aspects of inkjet recording systems is that they are considered non-impact recording systems. While an inkjet recording system has features that make high-speed recording possible; other attributes of inkjet recording systems are that they can perform recording on various recording media, and relatively no noises are generated while recording. Thus, an inkjet recording apparatus is widely employed as an apparatus serving as a recording mechanism of a printer, a copier, a facsimile, or a word processor.
An inkjet recording apparatus has been known, which employs an inkjet recording head cartridge provided integrally with an inkjet recording head unit configured to perform recording by discharging liquid, such as ink, and with an ink accommodating unit configured to supply ink to the recording head unit.
European Patent Publication No. EP1602486A1 discusses an inkjet recording head cartridge H100 that includes an ink accommodating unit whose inner space is partitioned into three chambers by a partition wall having a T-shape in plan view and that can accommodate different colors of ink, as shown in FIGS. 5A and 5B. A container body H501 of this cartridge has an L-shape in side view (see FIG. 5A) and also has a surface H201, on which a recording head unit H101 is disposed, on a projecting part H501a protruding from the bottom surface of the ink accommodating unit, which faces a cover H901. Openings through which ink is respectively supplied from associated chambers of the ink accommodating unit to the recording head unit H101, are provided in the surface H201. An ink flow path from each of the openings to a recording head is formed by providing a recording head unit H101. A discharge port array respectively corresponding to the chambers of the ink accommodating unit is formed in the recording head unit H101. Each color of ink is supplied from the associated chamber of the ink accommodating unit to the recording head through the associated ink flow path. A positioning unit H560 configured to perform positioning of the cartridge in the recording apparatus, and an electrical connection unit H302 configured to receive an electrical signal from a circuit of the recording apparatus are provided on a side surface H501b which is located at the side of the projecting part of the container body H501 in a direction intersecting with the discharge port array.
Also, U.S. Published Application No. 2006/0001711 discusses an inkjet recording head cartridge capable of accommodating at least four colors of ink.
Recently, it has been required that the inkjet recording system achieves high picture quality of the same level as a silver halide photograph. Thus, it has also been required that an amount of discharged liquid is reduced to a value which is equal to or less than, for example, 5 pl, and the resolution is raised to a high value (for example, about 1200×1200 dpi) to the extent that dots on a recording medium are hard to see (that is, grainy effects are unnoticeable).
In a case where such high-definition recording is performed, the distance between a discharge port surface, on which the discharge port array is provided, of the recording head in the recording apparatus, and a recording medium (that is, what is called a head-to-paper distance) is preferably as short as possible. In the recording apparatus that employs the inkjet recording head cartridge as discussed in the European Patent Publication No. EP1602486A1, conveyance members, such as a spur gear and a pinch roller, are provided to pinch the projecting part (H501a shown in FIG. 5A) of the cartridge. When intervals of supports for a recording medium are long, the recording medium is corrugated (or cockled) between the supports. Thus, it is necessary to secure a sufficient distance between the discharge port surface and the recording medium to prevent the discharge port surface from making contact with the recording medium. To reduce the distance between the discharge port surface and the recording medium, the distance (L1 shown in FIG. 5B) in the direction of the discharge port array of the projecting part, on which the recording head is disposed, is preferably short.
To reduce influence of an error caused when the cartridge is mounted in the recording apparatus, the distance (L2 shown in FIG. 5A) from a surface (H501b shown in FIG. 5A), on which the electrical connection unit is provided, in the vicinity of a reference surface, to the recording head unit H101 is preferably short.
Also, in addition to yellow ink, magenta ink, and cyan ink, high-quality print black ink differing in composition from black ink used to print characters can be employed as recording ink. Additionally, green ink and red ink may be used. To reduce a remaining amount of ink at the time of replacement of the cartridge, accommodated amounts of each color ink are preferably as equal as possible when a cartridge can accommodate more than three colors of ink including such additional ink.
However, it is difficult for the inkjet recording head cartridge discussed in the U.S. Published Application No. 2006/0001711 to simultaneously solve all of the above issues. A problem arises when high quality recording is performed by using this inkjet recording head cartridge. For example, as shown in FIG. 6, the distance L1 (see also FIG. 5b) in an inkjet recording head cartridge H200 whose inner space is divided by partitioning walls H701, H702, and H703 into four chambers, becomes long. When the distance L1 is reduced in this inkjet recording head cartridge, the capacity of ink accommodating units H601, and H602 at the side of the electric connection unit becomes small, as compared with the remaining ink accommodating units H603, and H604.